Fluorinated Graphene as High Performance Dielectric Materials and the Applications for Graphene Nanoelectronics

Abstract

There is broad interest in surface functionalization of 2D materials and its related applications. In this work, we present a novel graphene layer transistor fabricated by introducing fluorinated graphene (fluorographene), one of the thinnest 2D insulator, as the gate dielectric material. For the first time, the dielectric properties of fluorographene, including its dielectric constant, frequency dispersion, breakdown electric field and thermal stability, were comprehensively investigated. We found that fluorographene with extremely thin thickness (5 nm) can sustain high resistance at temperature up to 400°C. The measured breakdown electric field is higher than 10 MV cm−1, which is the heightest value for dielectric materials in this thickness. Moreover, a proof-of-concept methodology, one-step fluorination of 10-layered graphene, is readily to obtain the fluorographene/graphene heterostructures, where the top-gated transistor based on this structure exhibits an average carrier mobility above 760 cm2/Vs, higher than that obtained when SiO2 and GO were used as gate dielectric materials. The demonstrated fluorographene shows excellent dielectric properties with fast and scalable processing, providing a universal applications for the integration of versatile nano-electronic devices.

Graphene Oxide/Polystyrene Bilayer Gate Dielectrics for Low-Voltage Organic Field-Effect Transistors

“…Figure 3 shows the measured Ci and electric-field-dependent gate leakage current density. The Ci value of GO decreases from 85 to 62.4 nF cm -2 (average: 73.3 nF cm -2 ) and that of GO/PS decreases from 40.3 to 34.8 nF cm -2 (average: 37.8 nF cm -2 ), as the frequency increases from 10 kHz to 1 MHz, which agrees well with the reported Ci value of a GO film with a similar thickness [13]. Although the Ci value of the GO/PS bilayer is smaller than that of the GO film because of the low dielectric constant of PS, the former Ci is high enough for GO/PS to serve as a dielectric layer for low-voltage operation of OFETs.…”

“…On account of its outstanding electrical, mechanical, and chemical properties, graphene has been intensively studied for application as a semiconductor, electrode, and encapsulation layer in OFETs [4,[11][12][13][14]. In particular, graphene derived from graphene oxide (GO), which is referred to as reduced GO (rGO), has attracted much attention for application to flexible devices because of its thinness, excellent electrical properties, and mechanical flexibility [15][16][17].…”

Fluorinated Graphene Dielectric and Functional Layers for Electronic Applications

“…The dielectric constant of the films is determined to range from 1.1 to 3.2, depending on the fluorination degree of the material. It is important to mention that value of ε = 1.2 known for fluorographene [16,20], appears in our films for relatively low fluorinated degree (between C 4 F and C 2 F).…”

“…Graphene can be fluorinated by a low-damaged CF 4 plasma treatment [16] or by exposing the graphene to XeF 2 gas to convert it to insulating fluorographene (C 4 F) [17]. A new simple approach for graphene fluorination (treatment in aqueous solution of hydrofluoric acid) was recently suggested in Refs.…”

Electronic and optical properties of graphene nanoribbons in external fields

“…As magnetic fields are exerted, gap shrinkage happens and the GNR eventually undergoes a semiconductor-metal transition during the formation of Landau subbands. The gap modulation opens the possibility for the design of side-gated GNR-fieldeffect devices, [97][98][99][100][101][102][103] where the side gate offering a better alternative to top-gating scheme will prevent dielectric breakdown [104][105][106][107][108][109] and electrical hysteresis caused by top-gate dielectrics. [110][111][112][113][114][115][116][117][118][119][120][121] The geometric configurations and external fields not only modulate the gap but also alter the energy spacings among subbands.…”